Talk:Quadrilateral is Cyclic iff Opposite Angles sum to Two Right Angles

I'm not finding Sum of Angles in a Quadrilateral which could be useful here. In fact, it would be even better to have a proof for the sum of angles in a polygon, which I don't see either. --Telliott99 (talk) 11:14, 17 October 2023 (UTC)

Try Sum of Internal Angles of Polygon. They're called internal angles to distinguish them from external / exterior angles. --prime mover (talk) 16:14, 17 October 2023 (UTC)

I'd be grateful if you would rename this page. The question is, to what? In general, not clear on how to handle the case where we have an alternative proof for only one direction of an iff theorem. --Telliott99 (talk) 15:08, 1 November 2023 (UTC)